Cane-grinding mill



vJuly 12. 1927 l F. FARREL, JR

GANE GRINDINGMILL Filed May 2. 1921 Patented July 12, 1927. j

i UNITED STATES PATENT OFFICE. j

FRANKLIN FARREL, JR., OIE NEW I-IAVIEN,` CONNECTICUT, ASSIGNOR T0yFABREL FOUNDRY & MACHINE COMPANY, OF ANSONIA, CONNECTICUT.

CANE-GRINDING MILL.

Application led May 2,

This invention relates to cane grinding machinery such as employed forthe extraction of juice from sugar cane, and it has more particularapplication tofmills or grinding apparatus of the type .set forth in myapplication, Serial No. 445,527, filed February 16th, 1921, of which thepresent application isa continuation in part.

In some of its aspects the invention is especially applicable to canegrinding millsinv which one or more three-roll juice expressing millshaving a top roll, a cane roll and a bagasse roll, are preceded by apreliminary crusher having one or more pairs of rolls which crush thecane before it reaches said three-roll mill or mills.

In other aspects the invention concerns particularly the constructionand operation of a threerol1 grinding mill. j

One of the objects of the invention is to increase the extractiony ofjuice in a mill without commensurately increasing the area of rollsurface employed.

More specifically, my object is to increase the shredding of the canestalks in the mill so that the stalks will be more finely divided thanheretofore, and will form a mat of fine fibers from which the juice maybe more `"readily expressed as the` cane moves through the mill. thanhas been possible heretofore.

Another purposefof the invention is to provide a three-roll juiceexpressing mill with a differential drive which produces a frictionmotion on the cane Vand thereby increases the' shreddingY action on thelatter.

Another object of thev invention is to furnish an improved grinding millhaving one or more three-roll juice expressing mills ,and one or morepairs vof preliminary crusher rolls.`

To these and other ends the'invention consists in the novel features andcombinations of parts to vbe hereinafter describedv and claimed.

In the accompanying drawing: Fig. 1 is a fragmentary side` elevation,partly in section, of a cane mill embodying my improvements; v f

Fig. 2 is a fragmentary side elevation showing the roll driving gears;

Fig. 3 is a view similar to Fig. 1, showing a modified form; y

Fig. 4 is a fragmentary sectional view showing the grooving and spacingofthe fthe annular' grooves, teeth for hooking ldrawing in the cane sothat the latter will 1921. YSerial No. 465,958.

rolls ofthe three-roll mill illustrated in ysired, but in the particularembodiment now under discussion it may be assumed for purposes ofdescription, that the raw cane as 1t comes from the field .is deliveredto the vsingle pair of crushing rolls 1() by a suitable conveyor andchute (not shown). The

cane is drawn in and crushed bythe rolls 10, so as to split open thestalks and separate the fibers, and the stalks'then pass directly to themill B, consisting of the rolls 12, 13

and 14. The cane moves from the crusherV to the mill B over the ordinaryinclined bed, i

which I have not deemed it necessary to il- VIuStTate, andenters betweenthe rolls 12 andv 13, which are termed the top roll andcane rollrespectively. These rolls crush and: ex? press a portion of the juicefrom the cane,

' which as it leaves them is deflected upwardly in the customary mannerby the well known turn plate 15, so .as to passbetween i the top rolland the bagasse roll 14. It may vbe assumed for purposes of descriptionalso, although not necessarily so, that the installation is a large one,capable of handling imany tons. of cane daily, and that the mill B isfollowed by a plurality of similar juice expressing mills (not shown),there being suitable conveyors or carriers (not shown) between theseveral juice expressing mills,

in accordance with the usual practice.

The crushing rolls 10 may be of any approved type but preferably theywill be provided withl annular grooves, and with longitudinal groovesforming in connection with be fed into the machiney uniformly andexpeditiously. A suitable roll forv the purpose is shown in Fig. 5 andisdescribe'd in detailV in my application, Serial No. 445,527, pre-1Vviously mentioned." It has a plurality of cir.- cumferential grooves 10aand a plurality of generally longitudinal grooves 10b. The cirycumferential grooves of each crusher roll mesh with those of the otherroll, and the grooves 10" form interruptions in the circumferentialgrooves and create teeth that are adapted to hook or draw in the cane.

Viththe purpose of increasing the shreddi-n'g effect of the rolls, bothof the pi'feli-minary crushei', and f; rc'ea'oll mill, 'and ofaugment-ing the capacit-y of the machine, a differential motion of oneroll relatively to its mate or coacting roll is provided. One rollrotates at a n'iaterially greater surface speed than the roll on theopposite side of the cane stalk. rIhe result is that the fcane stalksare torn apart more thoroughly and more effectively shredded and openedup #so as to separate the individual fibers of the cane to aconsiderable degree; and by shredding the cane in this manner thefibersare put in a condition in which they will readily give up their juiceWhen they are subjected to the increased squeezing lact-ion of thefollowing rolls.

I believe 'that theb'est results are obtained Where the surface speed ofone crushing roll is at least 5% greater than that of its mate orcoacting roll, although .I do not Wish to limit myself unnecessarily inthis respect. In any case it may be said that in the machine shown inFig 1, one of the Crusher rolls has a surface-.speed substantiallygreater than its mate, and one of th'erolls'of the mill B .has a surfacespeed substantially 10 higher than that of a coacting roll. In theparticular form shown inl Fig. 1, the top crusher roll has a surfacespeed substantially 10% greaterthan that of the lower `crusher roll, andthevtop roll 12 hasa surface speed substantially 10% greater than thatof its coacting lower roll 13. In this particular case also, the speedof roll 12 is the same as that of bagasse roll l141. It Will be seentherefore that in the three-roll mill` as in the crusher,`circumfere'ntially gro'oved intermeshing upper and lower rolls havesurf-ace speeds which differ substantially from each other. I do vnotWish to limit myself., hoW- ever, in all of these respects, as'changesmay be made in the details Without departure from the principlesinvolved.

In the case under discussion the tivo coacting crusher rolls 10 are ofsubstantially the same diameter; and the three rolls fof mill kIi areall of lsubstantially the same diameter, which diameter will in practicelbe preferi ably but not necessarily slightly greater than the diameterof rolls 10. The diff-erential motion to which I have referred n'iay insuch a case be 'obtained by the use 'of intermeshing gears on the rollshafts, having a dissimilar number of teeth. Thevgear 10, by which theupper roll 10 is driven` has a somewhat smaller number of teeth than itscoacting gear 17, the difference in the number of teeth being so chosenas to bring about the relative roll speeds desired, the Idiffereter.

ence in this particular case being substantially 10%, as above statedThe lower roll 10 is driven by a shaft 18 on which gear 17 is mounted,the gear 16 heilig mounted on the shaft of the upper roll 10. The mill Bis driven from a shaft 19 vconnected With v'or carrying the roll 12,'anda 'gear 20 on said shaft meshes with a gear 21 on the shaft of caneroll 13 and With a gear on the shaft` of bagasse rollflei. In thisparticular oase,

the gear 21 has a larger number of teeth than the g'ears 20 and 22, suchnumber being so chosen as to effect the drive of the ktop roll 'at asurface speed which is 10% higher 'than that of the cane roll 13.

The grooving of the rol-ls 20, `21 and is shown in Fig. 4f. These'rollsare similar-to those shown in previous application, each being providedwith a plurality of annular f.

grooves, although inv this case I'have not shown the top roll .12asprovided with lon git-udin-al grooves as in the former clase These`longitudinal grooves mayv be employed, however, if desired, forincreasing" the hooking or drawing-in action Vonthe cane and grippingthesaine whilelthe cane passes through -the bitev of thcirolls 12, 13, andthen through the bite of the rol-1s 12, 14.

In the modified form shown in Fi 0'. 3, the

preliminary Crusher A ifs the saine fa-sthat '95 rpreviously described,but in thefthree-.r-oll mill Bf, the caneroll 13a, instead of being ofsubstantially 'the same diameter-as the other rolls of mill B is ofsomewhat smaller dia It has, .lioweveigthe saine number "of R. P. M.,owing to the fact that in th-iscase gears `(not shown) having-fan evennumber Yof teeth are mounted on the shafts of rolls 12, 13 andintermesln in Yaccordancewith the usual practice. In this manner, as in'the case previously described, the relative surface speed of the caneroll is decreased. *In

lsuch a mill, also, thesurface speed of the top roll is at least i5%greater than that of the cane roll and 'in this particular case the toproll surface speed is about 10% faster than the cane roll surface speed,asin the 'case previously described.

The operation of the grinding'm'ill will be more or less obvious'fromthe foregoing de scription. The difference in the surface speeds of therollsat opposite sidesof the rcane stalk 'produces a sort of tearingmotion yon the stalk, which I term la friction motion, `due to the factthat friction is exerted upon vthe stalk by one roll'while .it is lbeingheld by the veoacting roll. In the particular form-s shown, the `cane'isheld back in a sense by the lower Crusher' roll While it is 'being actedupon frictionally andtorn apartian'd shredded by the upper Crusher roll.In th-'e -mill Bor B', lon the other hand, tlie'top relil has a greatersurface speed faud'rvlle th'e stalks are held by the cane roll the' toprolll ribs tear them apart and shred them. in

IUS)

isthe slower one. I do lnot limit myself,

however, to such an arrangement, nor to three-roll mill in which thevtop rollhas a greater surface speed than. another roll.

Various changes in these and otherrespects may be made without departingfrom the scope of the invention Vas definedin the:

claims. a

It will be understood that as a general rule the crusher rolls areprovided with teeth and that the ribs of the upper and lower crusherroll are of the same pitch, corresponding somewhat to the top roll andbagasse roll of the three-roll mill, although usually the pitch isgreater than in the case of these particularA rolls of the three-rollmill. The cane roll is set farther apart from the top roll than isthebagasse roll, although the distance between the top roll and caneroll is usually somewhat less than thedistance between the two crusherrolls 10. As the top roll and bagasse roll are set quite closevtogether, they can exert a lpowerful squeezing action on the cane, andas the cane has been effectively shredded in the Crusher and in the biteof the top roll and cane roll, the squeez-` ing action in the closebiteof the top roll and bagasse roll of the three-roll mill is veryeffective in extracting juice.

It is preferred to increase the surface speed of the top roll relativelyto that of the cane roll, in the three-roll mill, on account of thetendency of the faster roll, i. e., top roll, to carry along the cane inthe same general direction as the curvature of the upper surface of theturn plate, which thus cleans olf the latter and prevents clogging. I donot limit myself, however, to this feature in all aspects of theinvention. By providing a friction motion on the cane between the toproll and cane roll, the cane is better conditioned, by the resultingshredding eect,`

for the subsequent heavy squeezing action, produced by the top roll incombination with the closely set bagasse roll. It may be foundadvantageous in certa-in cases,`however, to differentiate the surfacespeeds of the top roll and bagasse roll, respectively, for producing ashredding action which will be of value' in the following mill; andin-such a case, either the top roll'or the bagasse roll may be thefaster one. This surface speed diiference, also, may be effected bydissimilar toothing of the gears or by-difference in the roll diameters,as in the cases previously mentioned. y

The Crusher and the three-roll mill are provided with the usual or anypreferred hydraulic pressure devices, which I have not considered itnecessary to describe in detail, although they are shown in a generalway in the drawing. Usually the pressure between the top and: bagasserolls of the three-rollvmill. is greater than that between the rollsvofthe preliminary cruSher. The 'Y pressure inv the'preliminary Crusher maybe, say, 25); tons, whereas that in the first threeroll=mill maybe,say375 tons. f V

Y I am. aware Ythat inv prior threeroll and possiblyin preliminaryCrushers, kthere have been'surfacevspeed dierences betweencircumferentlally grooved mtermeshmg rolls.

caused by therunevenwearing of the roll surfaces, in certain instances,and in someY few cases there have perhaps been differences of surfacespeed resulting from inaccuracy in manufacture or similar causes. Insuch cases, however, so faras I am advised, the surface speed differencebetween coacting rolls has not amounted to, say, more than mills, l

one or two percent, usually less, and it has Usually it is moreconvenient to have the two coactingcrusher rolls of the same diameterand to drive them by gears having a dissimilar number of teeth asdescribed, but it isv obvious that in some cases the diiference ofsurface speed might be obtained by differences of diameter of theCrusher rolls, as explained in connection with the top and canev rollsof the three-roll mill of Fig. 3. Other changes in this and similarrespects may be made wit-hout departing from the scope of the inventionas defined in the claims.V Y

What I claim is:

l. A cane mill having a top roll, a cane roll and a bagasse roll, all ofsaid rolls being provided withannular grooves, the grooves of the topand bagasse rolls being of the same pitch but offset so that the ribs ofone of said two rolls extend into the grooves of the other, and thegrooves of the vcane roll being finer thanv the grooves of the top andbagasse rolls, the top roll and bagasse roll being set closer to eachother than to the cane roll, and means for driving the top roll and thebagasse roll at substantially greater' surface speed than that of thecane roll, thereby effecting a frictional shredding action upon the canepassing between the top roll and the cane roll.

2. A cane mill having a top roll, a cane roll having annular groovestherein, a bagasse roll, the top roll and bagasse roll lil() having.approxmately the :same surface rand being set 'einser to each otherthan the help y1'011 'is t@ the canelolhandmean's for delving the caneroll at 'a ysurface substimtay :slower than that lof the' tep andbagasse r01l's,\the'eby effecting auffietonal shredding 'a'eton upon5th-e v'Game passing `bet-Ween the top roll 'and Ithe 'cane r0=1=L4 InaYcane mill, movng'shreddngmemls l adapted to .have lcame passthereo-ver,said means ,having :a frib'bed Surface, the

movement lof Said eene, and Va pair ofco- @fptratmg 'rolls hav-mg ag1-eater suracej speed vthan Sald'shr'edding means 'and bemg adapted todrag @me over Said ribbed sur# l' face, ene 0i said rolls being:adaptedlto pressi the cane 'against said ribs While being'. drag-geilthereoven. In Witness whereof, I have hereunto seb my ha'ndY on the 28thdaye'f Aprl- 1921.,l FRANKLIN FARREL-JR.' y

